The exemplary embodiment relates to exchanging data with remote services such as multimedia databases and finds application when querying a database with a document which it is desired to maintain private.
In a typical remote service architecture, a user submits digital material to the remote service which processes the material and returns a result to the user. The business application architecture may vary depending on, for example, the service offered, the client device, and the bandwidth available between them. A remote service may be a web service which offers an interface to upload documents and download the results of processing them. For example, a user may submit an image to a remote service to find similar images. Another example is a mobile phone application which allows a user to submit captured images or sounds to a server which uses its increased processing power to process the data and send the results back to the device. Examples of remote services are image categorization, image retrieval (similar image search), product identification from images, music song identification from audio, and other services which accept other input formats (e.g., video).
Remote services raise privacy concerns when data to be uploaded is personal or confidential. For example, users of an image search service may refrain from submitting pictures in which they or their family appear. Similarly, a professional photographer may want to use an image search engine to check the originality of a photograph, but may hesitate to submit the photograph to an untrusted source. Similarly, a musician may be hesitant to submit a new composition to a music search engine.
Remote services could remedy this problem by providing privacy policies and by encrypting submitted data, but this is usually not the case as remote service providers generally benefit from acquiring the input data in order to improve their algorithms, augment their databases, or extract statistical information.
Because most public web services do not implement privacy-preserving mechanisms, there remains a need for a system which allows a user to query a web service without revealing a private document.